Method for making concrete pipe



1967 D. L. WELLING 3,300,560

METHOD FOR MAKING CONCRETE PIPE Filed NOV. 29, 1963 K/ZJ 34 IG. 3.

Patented Jan. 24, 19677 3,300,560 METHOD FOR MAKING CONCRETE PIPE Donald L. Welling, 519 S. 7th, Grand Haven, Mich. 49417 Filed Nov. 29, 1963, Ser. No. 326,733 7 Claims. (Cl. 264-336) This invention relates to a method for making concrete pipe. More particularly, this invention relates to a method for forming the ends of concrete pipes.

Several methods are presently utilized in the manufacturing of concrete pipe of the type utilized in storm sewers and the like. For example, the wet casting method utilizes a form filled with a wet mixture of concrete with a two or three inch slump, steam being applied to the form to accelerate curing and, as soon as the concrete has set enough to hold its own weight, the form is stripped and used over again. In this method, the pallet that forms the end of the pipe which the pipe sets on during curing is not taken off until the next day. Faster methods of manufacturing concrete pipe utilize packer heads or tamp machines or vibration. Such methods are old and wellknown to the art. For example, a packer head operation may run forty pipe per hour, each pipe having a thirty inch diameter and being eight feet long. Thus, in an eight hour day, 320 units could be manufactured. However, this means that the manufacturer must own 320 pallets since each pipe must set on the pallet forming its end overnight. At an average cost of $100 to $150'each, the capital investment would then of necessity run between $32,000 and $48,000 for pallets alone. Thus, the cost of this operation is excessive to all but very large pipe manufacters since it will be understood that the pallets just described are for one size pipe only. Upon multiplying this pallet investment by the number of sizes of pipe that a manufacturer must be ready to supply, it will be seen that pallet costs become prohibitive.

In addition, after pipes formed by these methods have stood on conventional pallets until completely cured (usually an overnight process), extreme difficulty is often experienced upon removal of the pallets. First of all, it is extremely diflicult to clean them off since completely cured concrete adheres to them. In addition, bits of concrete cracked off and adhering to the pallet mean that the formed end of the pipe is defective. The degree of defectiveness depends upon the size and location of the bits of concrete breaking off. Thus, the pipe must be carefully repaired by filling in these areas by hand which is laborious, time-consuming and consequently expensive. Thus, another cost factor is added to the pipe formed by the difficulty in cleaning off the pallets for reuse and by the repair necessary to the pipes formed. It will be seen that both the initial investment cost and the labor involved make it extremely difiicult for anyone other than a large pipe manufacturer to effectively utilize the improved, faster methods of making concrete pipe described hereinbefore.

It is therefore an object of this invention to provide an improved method for forming an end of a concrete pipe.

A further object of this invention is the provision of a method which greatly simplifies the cleaning of dies used in the forming of concrete pipes.

A still further object of this invention is the provision of a method which provides for the manufacture of an improved concrete pipe.

A further object of this invention is the provision of a method which greatly reduces the amount of work necessary to provide a finished concrete pipe.

These and other objects of this invention will become obvious to those skilled in the relevant arts upon reading the following specification in conjunction with the accompaying drawings, wherein:

FIG. 1 is a cross-sectional view showing the tongue and bell ends of concrete pipes secured together by means of a ring lying in a groovein the tongue end of the pipe;

FIG. 2 is a cross-sectional plan view of a pipe form and the split die of this invention for forming the tongue end of the concrete pipe shown in FIG. 1;

FIG. 3 is a cross-sectional view taken along the plane III III of FIG. 2; and

I FIG. 4 is a perspective view of an embodiment of the split die comprising a part of this invention.

Briefly, this invention relates to a method of fabricating a concrete pipe with 'a shaped end consisting in the steps of providing a pipe form, providing a die capable of being split apart and removably affixing the die in association with an end of the form, building the pipe with the form and removing the form from the pipe and the die. The pipe is then positioned for support on the die, and the die is split apart and removed from the pipe when the pipe is capable of supporting itself on its end. The improved structure provided is, in combination, a form for a concrete pipe and a die for forming an'end of a concrete pipe, the form including means for attachment to the die and the die including means for being split apart.

Referring more specifically to the drawings, the reference numeral 1 designates the tongue end of a concrete pipe, shown sealingly received into the bell end 2 of another similar concrete pipe in FIG. 1. Such concrete pipes are old and well-known for use in sewers and the like, the tongue end 1 including a shoulder 3 and a groove 4 extending around the outer circumference of the end 1. The bell end 2 of the adjacent pipe includes a shoulder 5, a heavy rubber ring 6 lying in the groove 4 and frictionally abutting the inner surface of the bell end 2. It will be seen that such structure sealingly secures the two adjacent pipes together. As shown in FIGS. 2-4, a split die 10 is provided for forming the tongue end 1 shown and described. It is to be specifically understood that the apparatus and method to be described hereinafter could be used in other applications for forming the ends of concrete pipes, the invention not being specifically limited to the formation of such tongue ends, the following being for purposes of description and illustration of an especially advantageous utilization of the method and apparatus.

In the embodiment shown, the split die 10 includes parts A and B, secured together by means of dowels 11. It will be seen, that with the use of dowels 11, the parts A and B can be secured together and detached from one another, forming a circular molding member. A groove 12 extends around the outer circumference of the split die 10, the purpose of which will be more fully explained hereinafter. On the interior circumference of the split die 10, the ridge 13 is provided for forming the tongue groove 4 described hereinbefore in a concrete pipe. The bottom 14 of the split die 10 is perfectly smooth and adapted to lie generally flush with the end of the pipe to be formed as will now be described in detail.

In the embodiment shown, an outer pipe form 20 is provided, the form 20 being of the type adapted to be used in a packer head machine of a type already in existence and well-known to the pipe forming art. The outer form 20 includes side walls 21 and a heavy steel die receiving members 22 at one end thereof. This entire structure is adapted to split along its length in a conventional manner, dowels 23 securing the structure together for positive attachment and detachment. Elongated, heavy pins 24 extend through the die receiving member 22 for extension into the groove 12 in the outer, circumference of the split die 10. It will be seen that the split die 10 is thus quickly and simply received by the pipe form 20, enveloping it securely. In addition, the pins 24 align the bottom 25 of the pipe form 20 with the bottom 14 of the split die 10. The die is positioned with respect to the form 20 so that the splits therein do not coincide with one another.

When the pipe form 20 has received the split die 10 in the manner shown and described, the empty pipe form is picked up with a fork truck or overhead crane and turned over 180 degrees so that the bell is in the bottom position. The form is inserted in the packer head machine with the bell end down and the roller head is then lowered, the bell forming header is raised and the machine is utilized in a conventional manner. When the pipe has been constructed in the conventional packer head manner, and the pipe is built, the form is picked off the machine, again by means of a fork truck or overhead crane, and once again turned 180 degrees so that the tonque end is now in down position. Before being so turned, a suitable apparatus may be inserted into the interior lower circumference of the pipe just formed for preventing interior movement or deformation thereof. This is not always necessary, but may take the form of a light steel band expanded to lie against the inner wall of the formed pipe (not shown). It will be seen from FIG. 3 that the bottom of the formed pipe, the bottom 14 of the split die 10 and the bottom 25 of the outer form 20 are all aligned one with the other. The structure as shown in FIG. 3 is then placed tongue end down on a smooth floor and by means of the dowels 23, the outer form 20 is split and stripped from the pipe just built. This leaves the pipe just built standing tongue end down resting to some degree on its own weight, but resting primarily on the bottom of the split die 10 itself. The newly formed pipe then rests on the smooth floor of the kiln and the curing process commences. The outer form 20 is of course immediately pressed back into the service of forming another pipe, a similar split die 10 being secured therein as described hereinbefore.

After an adequate time for curing, the concrete and the newly formed pipe can support its own weight. Depending on the various elemental conditions such as temperature, this takes from one to two hours. When the pipe is able to support its own weight, the split die 10 is removed from it by means of the dowels 11. Since the partially cured pipe is partially supporting its own weight, it is possible to knock the split die 10 away from the underside of the pipe. This is possible through the provision of the split die 10, together with the fact that the bottom 14 of the split die is aligned with the bottom of the pipe formed. When the split die 10 is separated from the formed pipe at this stage of curing, the die may be simply cleaned with a dry rag, rewaxed and used over again immediately. Not only does this greatly simplify the cleaning of the die, it further allows dies to be used from five to ten times per day depending on elemental conditions.

In maintaining pipe manufacturing plants, capital investment already run higher each year because of the different types of joints required. Thus, tremendous numbers of conventional pallets have been required. With the method and apparatus just described, the number of pallets required is easily cut in excess of eighty percent. For example, in a warm kiln the split dies'may be stripped from the newly formed pipe every hour. This means that the split dies may be used eight to ten times a day. Thus, the same production is achieved with forty of the split dies described hereinbefore as with up to 320 conventional pallets. This means an investment saving of $4,000 compared with $32,000$48,000. This savings is achieved with respect to just one type of pallet. This savings may be multiplied by the number of types of pallets formerly required.

In addition, labor saving costs have been astonishing. In the past, considerable manpower was required to remove several hundred pallets the morning after the pipes were formedto clean and oil the pallets removed and the like. It takes much longer to remove a pallet from a hardened concrete pipe that it does in the kiln. Further, the hardened concrete is much more difficult to clean from the pallet that when still in partially cured condition. It has been found that the time for removal and cleaning for reuse of the structure shown and described herein is approximately one-tenth of the time required for the removal and cleaning of a conventional pallet.

Still additionally, another very important improvement has been noted. When the split die is removed from the newly formed pipe before the concrete is completely cured, it is extremely easy to patch the pipe for improvements in appearance and function. First of all, removal of the split die at this stage of curing leaves the pipe in better shape. Secondly, it is usually necessary only to paint the newly formed pipe with cement and water paint, rubbing it off immediately after removal of the split die. This completely fills in irregular voids and gives a much improved marble-like appearance. Further, it gives the concrete a case hardened finish. As stated hereinbefore,

it has been extremely difficult to repair formed pipes in the past, both the function and appearance of such repaired pipes not being entirely satisfactory. These ad-' vantages have been achieved through the provision of a simplified structure and method as described hereinbefore.

While only certain embodiments of this invention and method have been shown and described, it may be possible to practice the invention through the utilization of certain other steps and methods which fall within the spirit and scope of this invention. Such other steps and embodiments are to be considered a part of this invention unless the following claims specifically state otherwise.

I claim:

1. A method of fabricating a concrete pipe with a shaped end consisting in the steps of providing an outer pipe form and an inner pipe form, providing a die capable of being split apart and fastened together by dowels and removably affixing said die within an end of said outer form, aligning the bottoms of said die and said outer form in a common plane, building the pipe within said outer form, removing said outer form from said pipe and said die, positioning said pipe for primary support on said die, and splitting said die and removing said die from said pipe is capable of supporting itself.

2. A method of fabricating a concrete pipe with a shaped end consisting in the steps of providing an outer pipe form and an inner pipe form, providing a die capable of being split apart and fastened together by dowels and removably afiixing said die within an end of said outer form, aligning the bottoms of said die and said outer form in a common plane, building the pipe within said outer form, removing said outer form from said pipe and said die, positioning said pipe for primary support on said die, providing means on the interior of said pipe at the end thereof hearing some of its own weight for strengthening said pipe, and splitting said die and removing said die trot]? said pipe when said pipe is capable of supporting itse 3. A method of fabricating a concrete pipe with a bell end and a shaped tongue end in a conventional pipe making machine of the type having an inner form consisting in the steps of providing an outer pipe form, providing a die for said shaped tongue end capable of being split apart and removably afiixing said die within an end of said outer form, placing said outer form on said machine bell end down, building the pipe within said outer form, removing said outer form from said machine, turning said pipe and said outer form tongue end down, positioning said pipe for support on said die, removing said outer form from said die, and splitting said die and removing said die from said pipe when said pipe is capable of supporting itself.

4. A method of fabricating a concrete pipe with a bell end and a shaped tongue end in a conventional pipe making machine of the type having an inner form consisting in the steps of providing an outer pipe form, providing a die for said shaped tongue end capable of being split apart and removably affixing said die within an end of said outer form, aligning the bottoms of said die and said outer form to lie in common planes, placing said outer form on said machine bell end down, building the pipe within said outer form, removing said outer form from said machine, turning said pipe and said outer form tongue end down, positioning said pipe for primary support on said die, removing said outer form from said die, and splitting said die and removing said die from said pipe when said pipe is capable of supporting itself.

5. A method of fabricating a concrete pipe with a bell end and a shaped tongue end in a conventional pipe making machine of the type having an inner form consisting in the steps of providing an outer pipe form, providing a die for said shaped tongue end capable of being split apart and secured together by dowels and removably affixing said die within an end of said outer form, aligning the bottoms of said die and said outer form to lie in common planes, placing said form on said machine bell end down, building the pipe within said outer form, removing said outer form from said machine, turning said pipe and said outer form tongue end down, positioning said pipe for primary support on said die, removing said outer form from said die, and splitting said die and removing said die from said pipe when said pipe is capable of supporting itself.

6. A method of fabricating a concrete pipe with a bell end and a shaped tongue end in a conventional pipe making machine of the type having an inner form consisting in the steps of providing an outer pipe form, providing a die for said shaped tongue end capable of being split apart and secured together by dowels and removably aflixing said die within an end of said outer form, aligning the bottoms of said die and said outer form to lie in common planes, placing said outer form on said machine bell end down, building the pipe within said outer form, removing said outer form from said machine, turning said pipe and said outer form tongue end down, positioning said pipe for primary support on said die, removing said outer form from said die, providing bracing means on the lower interior of said pipe for strengthening said lower interior thereof, and splitting said die and removing said die from said pipe when said pipe is capable of supporting itself.

7. A method of fabricating a concrete pipe with a bell end and a shaped tongue end in a conventional pipe making machine of the type having an inner form consisting in the steps of providing an outer pipe form, providing a die for said shaped tongue end capable of being split apart and removably afiixing said die within an end of said outer form, aligning the bottoms of said die and said outer form to lie in common planes, placing said outer form on said machine bell end down, building the pipe within said outer form, removing said outer form from said machine, turning said pipe and said outer form tongue end down, positioning said pipe for primary support on said die, removing said outer form from said die, and splitting said die and removing said die from said pipe when said pipe is capable of supporting itself, and painting the surface from which said die has been removed.

References Cited by the Examiner UNITED STATES PATENTS 1,126,355 1/1915 Beery 25127 1,225,182 5/1917 Schuettig 25127 1,427,945 9/ 1922 Cuozzo 249 1,799,697 4/ 1931 Moody 264-3 34 2,289,439 7/1942 Kogl 2643 34 3,096,555 7/1963 Gannaway 25-39 3,124,857 3/1964 Delisle 249100 3,201,844 8/1965 Poitras 25-39 ROBERT F. WHITE, Primary Examiner.

R. B. MOFFITT, Assistant Examiner. 

1. A METHOD OF FABRICATING A CONCRETE PIPE WITH A SHAPED END CONSISTING IN THE STEPS OF PROVIDING AN OUTER PIPE FORM AND AN INNER PIPE FORM, PROVIDING A DIE CAPABLE OF BEING SPLIT APART AND FASTENED TOGETHER BY DOWELS AND REMOVABLE AFFIXING SAID DIE WITHIN AN END OF SAID OUTER FORM, ALIGNING THE BOTTOMS OF SAID DIE AND SAID OUTER FORM IN A COMMON PLANE, BUILDING THE PIPE WITHIN SAID OUTER FORM, REMOVING SAID OUTER FORM FROM SAID PIPE AND SAID DIE, POSITIONING SAID PIPE FOR PRIMARY SUPPORT ON SAID DIE, AND SPLITTING SAID DIE AND REMOVING SAID DIE FROM SAID PIPE IS CAPABLE OF SUPPORTING ITSELF. 